DE102020112442A1 - Sensor warehouse, vehicle with this and method for evaluating measurement data from the sensor warehouse - Google Patents

Abstract

The present invention relates to a sensor bearing, comprising an inner bearing ring (01) which can be rotated about an axis and which is located coaxially with an outer bearing ring (02). A primary coil (09) and a microcontroller (06) are arranged on the rotatable inner bearing ring (01) and a secondary coil (11) is arranged on the stationary outer bearing ring (02). The primary coil (09) and the secondary coil (11) are arranged opposite one another, with an air gap (13) between them. Furthermore, the sensor bearing comprises a measuring element (04) which is coupled to the primary coil (09) and is arranged on an outer surface of the inner bearing ring (01). The invention further relates to a vehicle with at least one vehicle wheel and such a sensor bearing, as well as a method for evaluating a measurement signal from such a sensor bearing.

Description

The present invention relates to a sensor bearing. The invention also relates to a vehicle, in particular a passenger car, with one or more such sensor bearings and a method for evaluating measurement data that were acquired by means of the sensor bearing.

Rolling bearing arrangements with integrated sensor devices, also referred to as sensor bearings, not only realize the primary bearing function but also serve to record different bearing state variables, such as speed, temperature and angle of rotation. The sensor devices comprise several sensors and signal transmitters which are arranged on mutually opposite surfaces of the outer bearing ring and inner bearing ring.

In order to enable autonomous driving, among other things, measurement data from the wheel bearing or the wheel bearing environment should be used. In the case of trucks, for example, these measurement data are generated by means of a measuring ring attached to an axle journal, the axle journal standing and an outer ring arranged coaxially with it rotating. The measuring ring serves as a measuring sensor. A disadvantage of the described arrangement with a stationary measuring sensor is that no speed can be determined with it. Data from stationary measuring sensors have the disadvantage that they require a large number of sensors at different measuring positions in order to enable the full acquisition of measuring data. A large number of measurement positions is cost-intensive and requires a lot of effort to evaluate the recorded measurement data. Another disadvantage is that there is increased frictional contact, which can cause large hysteresis in the measurement signals. Furthermore, the measuring rate can be influenced, depending on the memory depth.

In the GB 2 531 259 A describes a method for detecting the distance between rolling elements in a rolling bearing.

In the DE 10 2014 212 124 B3 describes a transmitter for transmitting data and / or energy which comprises a concentric pair of coils. The coils are magnetically coupled and designed as a printed circuit on a multilayer circuit board.

the DE 103 23 889 A1 describes a rolling bearing with sensors for recording physical quantities acting on the bearing. Furthermore, the roller bearing comprises evaluation and / or transmission components, the components and sensors being arranged on a bearing component.

From the US 6,703,734 B2 a bearing is known in which a contactless signal transmission takes place from a rotating shaft to a standing shaft. The bearing includes a power generation circuit, a signal transmission circuit and an energy detection circuit.

the US 2018/0313708 A1 shows a storage unit for a vehicle wheel. The bearing unit comprises an inner bearing ring and an outer bearing ring as well as rolling elements located between them. Acceleration sensors are arranged on a rotating bearing ring.

From the WO 2004/070337 A1 a measuring bearing with an integrated data acquisition and data processing system is known. The measuring bearing has a recess in one of its bearing rings, in which a strain gauge is arranged.

the DE 10 2017 108 130 A1 describes a method for data fusion of a data set, the data originating from sensor measurements.

The submitted by the applicant DE 10 2018 128 648.1 describes a sensor bearing and a vehicle with this. The sensor bearing comprises a rotatable outer bearing ring and an inner bearing ring arranged coaxially to the outer bearing ring. A planar measuring point on which a sensor is arranged is formed on a circumference of the outer bearing ring. Furthermore, a microcontroller coupled to the sensor is arranged on the outer bearing ring. The sensor bearing further comprises a receiver coil arranged on the rotating outer bearing ring and a transmitter coil arranged on the inner bearing ring, the receiver coil and the transmitter coil being positioned opposite one another.

Telemetry systems for providing or transmitting signals and energy are known. Standard telemetry systems are usually multifunctional, have multiple channels and are therefore expensive. Wireless data transmission is called telemetry. A particularly simple telemetry system is, for example, a slip ring transmitter, the receiver and the transmitter being formed by the slip ring and a brush. The slip ring has sliding contact with a bearing ring. This system has the advantage that it is inexpensive. However, there is a high level of wear and tear, as a result of which a functional restriction is to be expected, and susceptibility to noise. Another known telemetry system for exchanging data and energy is radio telemetry. Wireless telemetry has the advantage that it works without wear. The disadvantage of radio telemetry is that it is more expensive than the slip ring transmitter and that a complex circuit is necessary. A third form of telemetry is inductive transmission; this also works wear-free. Inductive telemetry also requires interconnection and is considered too expensive, which is why it is not regularly used in sensor wheel bearings.

One object of the present invention, based on the prior art, is to provide a sensor bearing which has a suitable measuring position for sensors, it being possible for the sensors to be easily mounted in the bearing. A further object is seen in enabling inexpensive wireless signal transmission to such a sensor bearing. Furthermore, with the present invention, the acquisition and processing of measurement data of such a sensor bearing should be possible.

The stated object is achieved by a sensor bearing according to the attached claim 1 and by a vehicle with the sensor bearing according to the independent claim 8. Furthermore, the object is achieved by a method according to the independent claim 10.

The sensor bearing according to the invention comprises an outer bearing ring and an inner bearing ring located coaxially therewith. The inner bearing ring can be rotated relative to the stationary outer bearing ring. A primary coil is arranged on the inner bearing ring. A secondary coil is arranged on the outer bearing ring opposite the primary coil. An air gap, which is designed to be as small as possible, is formed between the primary coil and the secondary coil. Furthermore, the sensor bearing comprises a microcontroller which is arranged on the inner bearing ring and is connected to the primary coil by means of an electrical line. The primary coil is a receiver coil and the secondary coil is a transmitter coil, which serve as antennas for radio transmission or inductive data transmission. The primary coil and the secondary coil also serve to transmit and supply energy. Furthermore, the sensor bearing comprises a measuring element which is coupled to the primary coil. The measuring element is arranged on an outer surface of the inner bearing ring, at least a part of this outer surface forming a measuring point. The sensor bearing can be installed in a vehicle, in particular a car.

The outer surface of the inner bearing ring on which the measuring element is arranged is preferably formed by an outer circumference of the inner bearing ring. These areas are easily accessible during the manufacture of the sensor bearing and offer enough space for the measuring element. Alternatively, the outer surface is preferably an axial surface of the inner bearing ring, in particular the surface axially on a flange of the inner bearing ring. This area can be better protected from excessive loads occurring on the bearing.

The area of the outer surface on which the measuring element is arranged is preferably of planar design. This reduces the entry of undesired material stresses into the measuring element when it is attached. Alternatively, the area of the outer surface can also be designed to be curved. In particular with large radii, the attachment of the measuring element is thus possible in a simplified manner.

The measuring element is flat and largely does not require any installation space. The measuring element is preferably constructed as a thin-film sensor. The measuring element is preferably a strain gauge. The measuring element or the sensor particularly preferably consists of a stretch-sensitive metal coating which is arranged on the inner bearing ring. The stretch-sensitive metal coating is designed, for example, according to the so-called Sensotect series of the applicant. The advantage of using such a Sensotect coating as a measuring element is that no settling or fatigue effects occur.

An advantage of using flat measuring elements or sensors and their position on the bearing ring is that the recorded measured values are almost hysteresis-free. It is also advantageous to arrange the measuring element on the rotating bearing ring, since this allows more measured values or measurement information to be generated. Another advantage of using flat sensors is that they can be installed together with the sensor bearing in a simple and non-destructive manner. Known wheel bearing designs can advantageously be used.

The sensor warehouse is used to collect measurement data from the warehouse. A speed is determined by means of the measuring element. Furthermore, temperature, acceleration, load, position and direction of rotation can advantageously be detected with the measuring element at the defined measuring positions. Accordingly, sensors can be saved with the sensor bearing according to the invention, as a result of which costs and the space used are advantageously reduced. An additional ABS sensor can be omitted, for example. The driving dynamics control system of a vehicle can be improved by the additional measurement information.

The primary coil and microcontroller forming a processing unit are preferably cast together in a potting compound in order to protect them from environmental influences. The processing unit is particularly preferably encapsulated in a plastic carrier. In particular, they are Primary coil and the microcontroller are arranged together in a plastic carrier on the inner bearing ring or on the flange of the inner bearing ring. The primary coil and the microcontroller can be cast together in a plastic carrier on the inner bearing ring or on the flange of the inner bearing ring, whereby they are safely protected and positioned during installation in the vehicle and especially during permanent operation.

The secondary coil can also be at least partially cast in a potting compound, in particular in a further plastic carrier, with which the secondary coil is arranged on the outer bearing ring. The plastic carriers of the inner bearing ring and the outer bearing ring are spaced from one another.

Running surfaces and supports for seals can be integrated in the potting compound of the processing unit and / or the secondary coil. This facilitates the arrangement of external sealing elements.

The units are preferably potted before the final assembly of the sensor bearing.

The extension of the measuring element in the direction of rotation of the outer circumference of the inner bearing ring can vary depending on the desired function and can be easily adapted to the specific measuring requirements. The extension of the measuring element in the direction of rotation of the outer circumference of the inner bearing ring is preferably smaller than a diameter of a rolling element located between the outer bearing ring and the inner bearing ring. Alternatively, the extension of the measuring element in the circumferential direction of the outer circumference of the inner bearing ring is at least a quarter of the outer circumference of the inner bearing ring. The measuring element preferably extends between an extension smaller than a diameter of a rolling element and an extension of at least a quarter of the outer circumference of the inner bearing ring.

The measuring point or the area on which the measuring element is arranged is selected in such a way that expansions or material stresses on the outer surfaces of the sensor bearing can be measured.

In a preferred embodiment, the sensor bearing comprises a further measuring element which is designed in the same way as the first measuring element. In this embodiment, the sensor bearing accordingly comprises two measuring elements, the measuring elements being arranged at different measuring points or outer surfaces of the inner bearing ring.

The electrical interconnection of the multiple measuring elements can preferably be designed as a quarter or half bridge.

One advantage of using inductive telemetry is that it works without wear. The electrical interconnection in the sensor bearing advantageously offers energy-efficient and low-interference data transmission. The sensor bearing according to the invention is advantageous because only a small number of sensors is required for measuring, with a single sensor also being sufficient. Good measurement results are achieved and costs are saved.

The vehicle according to the invention has at least one vehicle wheel with a sensor bearing according to the invention, the sensor bearing being the same as the sensor bearing described above with all of its embodiments. The vehicle preferably comprises at least four vehicle wheels, each with such a sensor bearing. Each vehicle wheel can include more than one sensor bearing. The sensor bearing supports driver assistance systems installed in the vehicle.

The sensor bearing installed in the vehicle can preferably be arranged on the transmission side, alternatively preferably on the wheel side of the vehicle wheel. Alternatively, sensor bearings are arranged on the transmission side and on the wheel side of the vehicle wheel.

The vehicle is preferably a car. In a preferred embodiment, the vehicle is designed for autonomous driving.

The method according to the invention is used to evaluate a measurement signal from a sensor bearing. The sensor bearing is designed in accordance with the sensor bearing described above with all of its embodiments. The sensor bearing comprises an inner bearing ring with a measuring element arranged on it and an outer bearing ring as well as a microcontroller. The inner bearing ring rotates around the outer bearing ring. A first method step provides that a measurement signal is recorded by the measurement element of the sensor bearing. The measurement signal is essentially sinusoidal. The measuring element preferably detects a measured wheel bearing variable, such as a strain, a speed or an angular position. The recorded measurement signal is passed on to the microcontroller via an electrical connection in the next process step. In a further step, the microcontroller determines a peak-to-peak value of the measurement signal. In a subsequent process step, the peak-to-peak value is compared with the values stored in the microcontroller. Subsequently, in a further method step, a sensor bearing status is output based on the compared values.

In a further method step, the microcontroller can use the recorded measurement signal to determine measurement information on uneven road surfaces and / or vibrations and sensor bearing loads. In order to generate this measurement information, the uniformity of the sinusoidal signal is analyzed.

One advantage of the method according to the invention is that the measurement signals from a rotating signal source can be reproduced well. Furthermore, the system is hysteresis-free thanks to the sensor arranged directly on the outer bearing ring. Another advantage is that the peak-to-peak value is almost independent of temperature.

By means of inductive telemetry, with a receiver coil lying opposite a transmitter coil, the ascertained sensor bearing states are preferably passed on, for example to a control unit, in a further method step. The inductive telemetry advantageously also serves as an energy supplier for the microcontroller, so that an additional energy supply can be dispensed with.

• 1 einen Ausschnitt einer schematischen Schnittansicht einer ersten Ausführungsform eines erfindungsgemäßen Sensorlagers;
• 2 einen Ausschnitt einer schematischen Schnittansicht einer zweiten Ausführungsform des Sensorlagers;
• 3 eine Schnittansicht des Sensorlagers mit einem Messelement; und
• 4 eine Schnittansicht des Sensorlagers gemäß 3 mit einem alternativen Messelement.

Further advantages and details of the present invention emerge from the following description of preferred embodiments with reference to the drawing. Show it:

• 1 a detail of a schematic sectional view of a first embodiment of a sensor bearing according to the invention;
• 2 a detail of a schematic sectional view of a second embodiment of the sensor bearing;
• 3 a sectional view of the sensor bearing with a measuring element; and
• 4th a sectional view of the sensor bearing according to 3 with an alternative measuring element.

1 shows a detail of a schematic sectional view of a first embodiment of a sensor bearing according to the invention. The sensor bearing includes an inner bearing ring 01 and an outer bearing ring arranged coaxially with this 02 . The inner bearing ring 01 is opposite the outer bearing ring 02 rotatable. Between the two bearing rings 01 , 02 are rolling elements 03 arranged that the rolling of the bearing rings 01 , 02 serve each other. On the radial outer circumference of the inner ring 01 is a first flat measuring element 04 in the form of a thin-film sensor, which was generated by a stretch-sensitive metal coating, arranged. The first measuring element 04 is designed, for example, according to the Applicant's Sensotect series. The measuring element 04 is used to measure bearing parameters, such as a speed or an occurring strain. In terms of its dimensions and positioning, the measuring element is 04 preferably designed so that it is the outer circumference of the inner bearing ring 01 not towered over. This means that the outer bearing ring can still be installed in existing housing parts without these having to be adapted. The sensor bearing also includes a microcontroller 06 which is completely made of a plastic potting compound 07 is included. The microcontroller 06 is together with the plastic potting compound 07 on an axial end face of the inner bearing ring 01 arranged. The measuring element 04 is with the microcontroller 06 via an electrical connection 08 coupled. Furthermore, the sensor bearing comprises means for performing inductive telemetry in the form of a transmitter coil 09 or a primary coil, and a receiver coil 11 or a secondary coil. The two coils 09 , 11 serve together for data transmission and energy transfer. The transmitter coil 09 is on the outside of the plastic potting compound 07 arranged and is at least partially surrounded by this. The transmitter coil 09 is electrical with the microcontroller 06 tied together. Radially opposite the transmitter coil 09 is the receiver coil 11 arranged. The receiver coil 11 is in a second potting compound 12th at least partially embedded. Between the two coils 09 , 11 is a crack 13th educated.

1 shows the sensor bearing when it is positioned on a transmission side. The measuring direction of the measuring element 04 is in the in 1 The embodiment shown, for example, is divided into approximately 70% wheel contact force and 30% lateral force.

2 shows a detail of a schematic sectional view of a second embodiment of the sensor bearing, the sensor bearing being positioned on one side of the wheel.

First of all, it is the same as in 2 sensor bearings shown in 1 sensor bearing shown. In contrast to the in 1 The sensor bearing shown in FIG 2 Sensor bearing shown a second measuring element 14th , which is the first measuring element 04 preferably the same in design. But it is also possible that the two measuring elements 04 , 14th are of different design or function. The additional measuring element 14th is on an axially extending surface or a flange 16 of the inner bearing ring 01 arranged. The two measuring elements 04 , 14th are aligned orthogonally to each other. The measuring direction of the measuring element 04 in the in 2 The embodiment shown is similar to that in FIG 1 embodiment shown. The measuring direction of the measuring element 14th is in the in 2 The embodiment shown, for example, is divided into approximately 25% wheel contact force and 75% lateral force.

3 FIG. 4 shows a sectional view of the sensor bearing according to FIG 1 or 2 with a Measuring element 04 , 14th , with the measuring element 04 , 14th in the circumferential direction to a quarter over the circumference of the inner bearing ring 01 extends.

4th initially equals 3 - 4th FIG. 4 shows a sectional view of the sensor bearing according to FIG 1 or 2 with an alternatively designed measuring element 04 , 14th , with the measuring element 04 , 14th in the circumferential direction less than a diameter extension of a rolling element 03 over the circumference of the inner bearing ring 01 extends.

List of reference symbols

01

Inner bearing ring

02

Outer bearing ring

03

Rolling elements

04

first measuring element

05

-

06

Microcontroller

07

Plastic potting compound

08

electrical connection

09

Transmitter coil

10

-

11

Receiver coil

12th

second potting compound

13th

gap

14th

second measuring element

15th

-

16

axial surface / flange of the inner bearing ring 01

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• GB 2531259 A [0004]
• DE 102014212124 B3 [0005]
• DE 10323889 A1 [0006]
• US 6703734 B2 [0007]
• US 2018/0313708 A1 [0008]
• WO 2004/070337 A1 [0009]
• DE 102017108130 A1 [0010]
• DE 102018128648 [0011]

Claims (10)

Sensor bearing comprising an inner bearing ring (01) which is rotatable about an axis and which is located coaxially to an outer bearing ring (02), characterized in that a primary coil (09) and a microcontroller (06) on the rotatable inner bearing ring (01) and on the stationary outer bearing ring (02) a secondary coil (11) are arranged, the primary coil (09) and the secondary coil (11) being arranged opposite one another and an air gap (13) between them and a measuring element (04) coupled to the primary coil (09) on a outer surface of the inner bearing ring (01) is arranged. Sensor bearing after Claim 1 , characterized in that the outer surface of the inner bearing ring is an outer circumference of the inner bearing ring (01) or an axial surface (16) of the inner bearing ring (01). Sensor bearing after Claim 1 or 2 , characterized in that the measuring element (04) is flat and space-neutral in relation to the outer dimensions of the sensor bearing. Sensor bearings according to one of the Claims 1 until 3 , characterized in that the measuring element (04) is a strain gauge or consists of a strain-sensitive metal coating. Sensor bearings according to one of the Claims 1 until 4th , characterized in that the sensor bearing comprises at least one further similarly designed measuring element (14) which is arranged on an outer surface of the inner bearing ring. Sensor bearings according to one of the Claims 1 until 5 , characterized in that the extension of the measuring element (04) in the direction of rotation of the outer circumference of the inner bearing ring (01) is smaller than a diameter of a rolling element (03) located between the outer bearing ring (02) and the inner bearing ring (01). Sensor bearings according to one of the Claims 1 until 5 , characterized in that the extent of the measuring element (04) in the direction of rotation of the outer circumference of the inner bearing ring (01) is at least a quarter of the outer circumference of the inner bearing ring (01). Vehicle, in particular a car, with at least one vehicle wheel, which is a sensor bearing according to one of the Claims 1 until 7th includes. Vehicle after Claim 8 , characterized in that the sensor bearing is arranged on the transmission side and / or on the wheel side of the vehicle wheel which comprises the sensor bearing. Method for evaluating a measurement signal according to one of the Claims 1 until 7th formed sensor bearing, which has an inner bearing ring (01) with a measuring element (04) arranged thereon as well as an outer bearing ring (02) and a microcontroller (06), comprising the following method steps: - Detection of the measuring signal by the measuring element (04), the measuring signal being sinusoidally shaped is; - Transmission of the measurement signal to the microcontroller (06); - Determination of a peak-to-peak value of the measurement signal by the microcontroller (06); - Comparing the peak-to-peak value with comparison values to which the microcontroller (06) has access; and output of a sensor bearing status based on the compared values.

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